Fully fluorinated hydrocarbon derivatives (perfluorocarbons) are used worldwide in a variety of domestic and industrial applications. As a consequence of such use gaseous perfluorinated hydrocarbons are currently being released to the environment. As an example, low molecular weight perfluorocarbons are used in combination with oxygen in the semiconductor manufacturing industry for silicon chip etching and for cleaning chemical vapor deposition chambers. These processes are typically conducted under vacuum. The exhaust gas from the chamber contains, in addition to the perfluorocarbons, unreacted deposition compounds and a variety of reaction products, such as hydrogen fluoride, nitrogen trifluoride, etc. Since these compounds cannot be safely released to the atmosphere the exhaust gas is generally treated to destroy the potentially harmful compounds or convert them to compounds that can be released to the atmosphere. According to one procedure, the gas stream is introduced into a reactor such as the gas reactor column manufactured by Edwards High Vacuum International Division of The BOC Group, plc under the trade designation EDWARDS GRC, wherein components of the stream are reacted at high temperatures and converted into disposable solid substances. Perfluorocarbons are highly nonreactive, however, and pass through the reactor unaffected. Since perfluorocarbons are nontoxic and are not believed to be harmful to the ozone layer surrounding the earth they are currently discharged to the atmosphere.
Perfluorocarbons are considered global warmers, however, because of their high stability and thermal characteristics. Accordingly, industry worldwide is now making efforts to minimize or discontinue release to the environment of perfluorinated hydrocarbons. Since currently available processes for recovering these compounds from waste gases are costly and not always practical, methods of destroying them have been considered. One proposed method of destruction is combustion. This would be accomplished by heating them to temperatures in excess of 1000.degree. C., which temperatures would be attained by burning hydrogen and oxygen in the presence of the perfluorocarbons.
Destruction of perfluorocarbons is not the best solution to the disposal problem because it is expensive, and incomplete combustion may result in the production of other harmful byproducts. Furthermore, perfluorocarbons are high value products and could be profitably recycled, if they could be recovered from gas streams at reasonable cost. The present invention provides a cost effective and efficient method of accomplishing this objective.